1. Base editing HbS to HbG-Makassar improves hemoglobin function supporting its use in sickle cell disease.
- Author
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Kostamo Z, Ortega MA, Xu C, Feliciano PR, Budak E, Lam D, Winton V, Jenkins R, Venugopal A, Zhang M, Jamieson J, Coisman B, Goldsborough K, Hernandez B, Kanne CK, Evans EN, Zgodny J, Zhang Y, Darazim J, Patel A, Pendergast MA, Manis J, Hartigan AJ, Ciaramella G, Lee SJ, Chu SH, and Sheehan VA
- Subjects
- Animals, Mice, Humans, Disease Models, Animal, Male, Mutation, Mice, Inbred C57BL, Female, Hypoxia genetics, Anemia, Sickle Cell genetics, Anemia, Sickle Cell therapy, Anemia, Sickle Cell blood, Gene Editing methods, Hemoglobin, Sickle genetics, Hemoglobin, Sickle metabolism, Erythrocytes metabolism, Hemoglobins, Abnormal genetics, Hemoglobins, Abnormal metabolism
- Abstract
Adenine base editing can convert sickle hemoglobin (HbS, βΕ6V) to G-Makassar hemoglobin (HbG, βE6A), a naturally occurring variant that is clinically asymptomatic. However, the quality and functionality of purified HbG and of mature HbGG and HbGS red blood cells (RBC) has not been assessed. Here, we develop a mouse model to characterize HbG. Purified HbG appears normal and does not polymerize under hypoxia. The topology of the hemoglobin fold with the βΕ6Α mutation is similar to HbA in the oxy and deoxy states. However, RBC containing HbGS are dehydrated, showing altered function and increased sickling under hypoxia. Blood counts and mitochondrial retention measures place HbGS RBCs as intermediate in severity between HbAS and HbSS, while organ function is comparable to HbAS. HbGG resembles HbAA for most metrics. Our results highlight the importance of functionally assessing the mature red cell environment when evaluating novel gene editing strategies for hematologic disorders., Competing Interests: Competing interests: All authors from Beam Therapeutics disclose a conflict of interest and are shareholders of Beam Therapeutics. The remaining authors declare no competing interest., (© 2025. The Author(s).)
- Published
- 2025
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